In general, the current design of a polishing head of a chemical-mechanical polishing system allows a control on its polish profile. However, this control only allows for the zones along the radial directions. Thus, there is a problem when there is an asymmetric topography of the polish profile.
On the other hand, the current method of profile control utilizes the deformation of the membrane by pneumatic mechanism. However, the application of pneumatic pressure is sometimes technically out of control, affecting the polish profile of the polishing head.
Therefore, there is a need to solve the above deficiencies/problems.